Shorten thread names that exceed the 15-char Linux limit

[danmoseley]

Note

This issue was created with Copilot assistance.

Linux limits thread names to 15 characters (plus null terminator) via pthread_setname_np. Several runtime thread names exceed this and get silently truncated, making them indistinguishable in debuggers and diagnostic tools like ps, top, and htop.

(macOS allows 63 chars, FreeBSD allows 32 — Linux is the strictest.)

Current Name	Len	Suggested Name	Len	Location
.NET Stack overflow trace logger	33	.NET SO Tracer	14	src/coreclr/vm/eepolicy.cpp
.NET Stack overflow create dump	32	.NET SO Dumper	14	src/coreclr/vm/excep.cpp
.NET Tiered Compilation Worker	30	.NET Tiered JIT	15	src/coreclr/vm/tieredcompilation.cpp
.NET Long Running Task	23	.NET Long Task	14	ThreadPoolTaskScheduler.cs
.NET ThreadPool IO	18	.NET TP I/O	12	PortableThreadPool.IO.Windows.cs
.NET SynchManager	17	.NET Synch Mgr	14	src/coreclr/pal/src/synchmgr/synchmanager.cpp
.NET TP Worker	14
.NET Finalizer	14
.NET EventPipe	14
.NET DebugPipe	14
.NET Debugger	13
.NET TP Gate	12
.NET TP Wait	12
JSWebWorker	11
.NET Timer	10

Note: The managed debugger may rely on some of these thread names to identify special threads. If so either they should be left unchanged or there will need to be a synchronized debugger change to match.

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[jkotas]

.NET TC Worker

We should drop the "worker" from the name, it has very little information value. Once we do that, it can something more self-describing like ".NET Tiered JIT".

.NET LR Task

"LR" is very cryptic. Can this be something more self-describing like ".NET Long Task"?

.NET TP I/O

Windows specific. (We can still change the name to make it more similar to other TP names.)

[danmoseley]

Any issues with debugger dependency or we can freely change?
I can kick copilot if there's no special considerations

[jkotas]

We have tweaked the thread names a few times before and I do not recall debugger or diagnostic tools having an issue with that.

[danmoseley]

@Copilot please change names as per the table above